Studies On The Synthesis And Properties Of CoFe Alloy Nanocomposities

CoFe alloy nanoparticles (NPs) have received considerable attention to researchers in both academia and indurstry due to their potential technological applications including magnetic and electronic devices, biotechnology, and catalysis. Traditional syntheses of alloy nanocomposites including sol-gel, co-precipitation and impregnation-reduction methods are based on mixtures of precursors, and consequently, control over the purity and composition of the resulting alloy nanocomposites is very difficult. And most of the systems involve organometallic precursors, the multi-step synthesis of which is time-consuming and high-cost, and involves environmentally unfriendly chemicals.In this work, we present a new approach to prepare CoFe/MgO,CoFe/Al2O3 alloy nanocomposites from single-source inorganic LDHs intercalated with CO32-. The main results are as follows:(1) CoFe/MgO nanocomposites were prepared using MgCoFe-CO3-LDHs as single precursors and we studied the structure of the nanocomposites at different reduction conditions. CO32-decomposed completely at 450℃, CoFe/MgO was composed of bcc-CoFe alloy and MgO crystal matrix. When the temperature reached 700℃,The bcc tured to fcc structure. In this article, we obtained CoFe/MgO nanocomposites at lowe temperature and the ultra-small CoFe alloy nanoparticles are uniformly dispersed throughout the MgO matrix.(2) The control of the composition of the CoFe alloy nanocomposites were freely manipulated by tailoring the molecular composition of the MCoFe-LDHs precursors. We obtained CoFe/Al2O3 nanocomposites by changing Mg to Al; We controled the composition (Co/Fe=0.5,1, 2) and the proportion of CoFe alloy (51%～87%) by changing the ratio of M/Co/Fe;(3) The magnetic properties of the CoFe alloy nanocomposites were investigated in this article. The nanocomposites are ferromagnetic, the coercivities are higher than that a single crystalline CoFe alloy due to the strong surface effects in the very small CoFe alloy nanoparticles; their saturation magnetization increases with the proportion of CoFe alloy and have the best saturation magnetization when Co/Fe=1.